Ch.12 Learn Smart

The central nervous system is made of the _______ and spinal ______.

brain cord

Dendrites branch off the _____

cell body

The ependymal cells help produce ______.

cerebrospinal fluid

The epineurium is made of ____ connective tissue.

dense irregular

Match the location with the larger concentration or ions. extracellular --> sodium intracellular --> organic ions

extracellular = sodium intracellular = organic ions

The chromatophillic substances help create the ______ color in parts of the brain and spinal cord.

grey

The myelin sheath is made of a high percentage of _____.

lipids

Most motor neurons are

multipolar

The presence of a _______ sheath increases the rate of impulse condition.

myelin

The thin outer layer of the neurolemmocyte is called the _______.

neurilemma

The ability to alter a response of neurons to neurotransmitters is known as

neuromodulation

In neurons, most chemically gated ion channels open in response to the binding of a(n) _______

neurotransmitter

The neuron cell body houses the _______ and the cytoplasm.

nucleus

During the _____ _______ an axon is either incapable of generating an action potential, or requires a larger than normal stimulus.

refractory period

The period following an action in which an action potential can be initiated with a larger stimulus is known as the ______ _____ period.

relative refractory

Receptors....

send information to sensory neurons.

The process by which postsynaptic potentials are added together at the initial segment is known as ______.

summation

Nerve Type A

- Conduction velocity up to 150 meters per second - Large diameter myelinated

Which of the following are functional classes of neurons? Check all that apply. - Motor neurons - Interneurons - Multipolar neurons - Bipolar neurons - Sensory neurons - Unipolar neurons

- Motor neurons - Interneurons - Sensory neurons

Nerve Type C

- Slowest conduction velocity - Unmyelinated

______ of our neurons are interneurons.

99%

A ______ is the propagation of an action potential along an axon.

A nerve impulse

______ are star shaped.

Astrocytes

The postsynaptic potential immediately follows the binding of neurotransmitter molecules that can _____.

Both be excitatory and inhibitory.

Identify all of the components of the central nervous system. Check all that apply. 1- Spinal nerves 2- Brain 3- Spinal cord 4- Cranial nerves

Brain and spinal cord

A positive change in the membrane potential is called________.

Depolarization

The _____ the resistance, the _____ the current.

Higher, lower

Which of the following pumps can you find in the plasma membrane?

Na+/K+ Ca2+

A return of the membrane potential towards the resting membrane potential immediately following depolarization is called ______.

Repolarization

Place the events of synaptic transmission from earliest to latest. 1- Neurotransmitter diffuses across synaptic cleft. 2- Action potential reaches synaptic knob. 3- Voltage-gated calcium channels open 4- Calcium triggers exocytosis of vesicles. 5- Calcium enters the synaptic knob. 6- Neurotransmitter binds to postsynaptic receptors.

2,3,5,4,1,6

Place the events of an EPSP in order. 1- More Na+ enters the postsynaptic cell than K+ leaves. 2- Excitatory neurotransmitter binds to chemically gated cation channel. 3- The inside of the cell becomes more positive. 4- The local current of Na+ becomes weaker as it moves towards the axon hillock.

2- Excitatory neurotransmitter binds to chemically gated cation channel. 1- More Na+ enters the postsynaptic cell than K+ leaves. 3- The inside of the cell becomes more positive. 4- The local current of Na+ becomes weaker as it moves towards the axon hillock.

The neuron in the retina of the eye are______.

Bipolar

The presence of ______ ions causes the synaptic vesicles to bind to the membrane, causing neurotransmitters to be released.

Calcium

Satellite cells are found surrounding________.

Cell bodies

Ependymal cells produce and circulate cerebrospinal fluid. The _______ helps circulate the CSF.

Cilia

the total length of the axon is called the_______ segment.

Conductive

Axon

Conducts information away from the cell body

Dendrites

Conducts information to the cell body

_______ occurs in an unmyelinated axon.

Continuous conduction

Which terms are used for the structural classification of nerves?

Cranial and Spinal

Choose which of the following can be the mechanism by which neurotoxins may do harm. Check all that apply. -Alter events that occur at a synapse - Induce detrimental structural change to a neuron - Increase protein synthesis - Interfere with transmission of action potentials - Potassium channels may be blocked

-Alter events that occur at a synapse - Induce detrimental structural change to a neuron - Interfere with transmission of action potentials

Which of the following are considered types of effectors? -Glands - Skeletal muscle -Cardiac muscle - bone tissue

-Glands - Skeletal muscle -Cardiac muscle

Which of the following is used for fast axonal transport?

-microtubules -motor proteins -ATP

The nervous tissue of a young adult may contain up to _______ glial cells

1 trillion

Place the events of a chloride-based IPSP in order from earliest to latest.

1- Inhibitory neurotransmitter binds to postsynaptic chemically gated chloride channels 2- Chloride moves from outside the cell to the inside 3- The inside of the postsynaptic cell becomes more negative. 4- The local chloride current becomes weaker as it moves away from the neurotransmitter binding site.

Which of the following are true of neurolemmocytes? Check all that apply. 1- They create the myelin sheath in the PNS. 2- They create cerebrospinal fluid. 3- They are also called Schwann cells. 4- They surround cell bodies.

1- They create the myelin sheath in the PNS. 3- They are also called Schwann cells.

Synapses are classifies as: Check all that apply. 1- electrical synapses 2- mechanical synapses 3- chemical synapses

1- electrical synapses 3- chemical synapses

Numerous _____must be generated and arrive at the initial segment at nearly the same moment if threshold is to be reached.

EPSPs

The tissues that receive nerve impulses from motor neurons are called _______.

Effectors

The motor nervous system is also referred to as the _____ division.

Efferent

The electrochemical gradient is formed from a combination of the ______ gradient and the _____ gradient.

Electrical, Chemical

The net diffusion of a given ion is dependent upon its ______ _____.

Electrochemical gradiant

Synaptic knobs are also called :

End bulbs and terminal boutons

An individual axon is wrapped in a connective tissue covering called the ______.

Endoneurium

True or False: Neurons far outnumber glial cells.

FALSE

When chemically or voltage gated channels open, there is a change in ion _____ across a membrane

Flow

Repolarization is due to the opening of voltage-gated ____ and the subsequent movement of ____ out of the cell.

K+/K+

________ channels allow ungrated flow of specific ions from region of high concentration to regions of low concentration.

Leak

______ cells wander through the CNS and replicate in response to an infection.

Microglia

________ represent the smallest percentage of CNS glial cells.

Microglia

The ____ consists of all axons that transmit a nerve impulse from the CNS to a muscle or gland.

Motor nervous system

______ is an autoimmune disease causing destruction of the myelin sheath in the central nervous system.

Multiple sclerosis

Which of the following ions have leak channels on the plasma membrane? - Ca2+ - Na+ - H+ - K+

Na+ K+

The nerve impulse has the voltage-gated ____ channels opened first followed by the opening of the voltage-gated ______channels.

Na+/ K+

In the ____there are a lot of ion channels and very little myelin.

Neurofibril node

The small spaces that interupt the myelin sheath are called _______.

Neurofibril nodes

Neurofilaments aggregate to form bundles called ________.

Neurofibrils

_______ is/are considered "nerve glue".

Neuroglial cells

______ is the name of the glial cell surrounding the axon.

Neurolemmocyte

______ are excitable cells that initiate and transmit electrical signals.

Neurons

_____ is the return of polarity from positive back to negative (the RMP).

Repolarization

_______ are found in mixed nerves.

Sensory and motor axons

The flow of ______ ions is the most common cause of depolarization. - Chloride - calcium - sodium - potassium

Sodium

An action potential cannot be initiated during the absolute refractory period because ______.

Sodium channels are inactivated, and thus can not open

A change in membrane potential insufficient to cause an action potential is known as a _____ ______.

Subthreshold value

______ (is) are the slightly expanded region at the tip of the fine terminal extensions of a neuron.

Synaptic knobs

True or false: The flow of potassium ions through leak channels makes the membrane potential more negative.

TRUE

If several EPSPs occur at a synapse over a short period of time, they undergo _____ at the initial segment.

Temporal summation

Substances can be moved in fast axonal transport (in) ______.

antergrade and retrograde directions

Voltage-gated sodium channels _______ during the relative refractory period.

are returning to the resting state

Axons collaterals ________.

are side branches off of an axon

In the initial segment, an action potential is generated if the membrane potential reaches the ______ ______.

Threshold value

Sensory nerves carry information ______.

To the central nervous system

Axon hillock

Triangular region connecting the axon to the cell body

TRUE or FALSE In most cases, a single EPSP is not sufficient to cause a neuron to reach the threshold potential.

True

True or False: Most voltage-gated ion channels are closed until the electrical potential across a membrane changes.

True

A unipolar neuron has one extension. A bipolar neuron has _______ extensions.

Two

Sensory information from the visceral sensory division is ______ sensed.

Unconsciously

_______ neurons have a single, short neuron process that emerges from the cell body and branches like a T.

Unipolar

The _______ functional division of the nervous system transmits information from the viscera to the central nervous system.

Visceral sensory division

__________ are essential for the generation of an action potential.

Voltage gated channels

_______ is what underlies the absolute refractory period.

Inactivation of sodium channels.

Many local anesthetics prevent the transmission of pain by ______.

Inhibiting voltage gated sodium (Na+) channels

The "I" in IPSP stands for ______, meaning that the potential makes the inside of the postsynaptic cell more _____.

Inhibitory, negative

The sensory division of the nervous system is responsible for __________.

Input

______ there would be no net movement of K+ ions through an open K+ leak channel.

When the electrical gradient and chemical gradient balance each other.

The components of the somatic sensory division are:

_Hearing - taste - joints and muscles

The synaptic knob is found ______.

at the extreme tips of the axon

The plasma membrane of an axon is called the ______

axolemma

The peripheral nervous system is made of the spinal nerves, ganglia, and _______ nerves.

cranial

The perikaryon is another name for the ______ in the cell body of a neuron.

cytoplasm

Motor neurons are classified as ______ neurons.

efferent

A myelinated axon has a ______ conduction velocity than an unmyelinated axon.

faster

neurons are classified ______ depending on the direction the nerve impulse travels.

functionally

If you were moving across a neurons's membrane from the receptive segment toward the transmissive segment, in the ____ is where would you first encounter large numbers of voltage gated Na+ and K+ channels.

initial segment

The changes in membrane potential associated with both EPSP and IPSP inputs are "added" in the _____ to determine if an action potential is initiated and the threshold is reached.

initial segment

As more neurotransmitter is released,______ channels open in the postsynaptic neuron.

more

______ are intermediate filaments that aggregate to form bundles called neurofibrils.

neurofilaments

Chromatophillic substances and Nissl bodies are both types of _______.

ribosomes

A nerve impulse that "jumps" from node to node is called ______ conduction.

saltatory

Interneurons facilitate communications between _______ neurons and _______ neurons.

sensory motor

Glial cells are both ______ than neurons and capable of ______.

smaller/mitosis

Axoplasm

the cytoplasm of the axon

If summated PSPs reach threshold, an action potential begins first in _____.

the initial segment

Dendrites transfer information______ the cell body.

toward

Vesicles involved in retrograde transport are moving _______ the cell body.

toward

The _____ division of the nervous system is subdivided into the sympathetic and parasympathetic divisions.

Autonomic

The ______ is sometimes called the nerve fiber.

Axon

Nerve Type B

- Medium Conduction velocity - Conduction velocity of approximately 15 meters per second

The functions of astrocytes are to Check all that apply. - Regulate the composition of interstitial fluid. - Myelinate axons of the PNS - Produce cerebrospinal Fluid - Help from the blood- brain barrier - Assist neuronal development

- Regulate the composition of interstitial fluid. - Help from the blood- brain barrier - Assist neuronal development

Which of the following segments of a neuron contain large numbers of voltage-gated potassium channels and voltage-gated sodium channels? - The conductive segment. - The transmissive segment - The initial segment - The receptive segment

- The conductive segment. - The initial segment

The voltage gated sodium channels undergo changes in activity during the depolarization phase of an action potential. Place these in order from first to last.

- The membrane potential is -70 mv. - Sodium ions flow into the neuron - The membrane potential becomes more positive. - Voltage gated sodium ion channels open

What must happen in order for a chemical signal to change the membrane potential of a neuron?

- There must be a change in ion flow across the membrane. - there must be change in the number of open ion channels

the leak of potassium ions tends to drive the membrane potentials to -90 millvolts, and yet the normal resting membrane potential (RMP) of a neuron is around -70 millvolts . What is the reason for this difference?

A small leak of sodium ions make the RMP more positive.

Match the structure with the appropriate letter. Drag statements on the right to match the left. A- Axon B- Terminal extensions C- Axon collateral D- Synaptic knobs E- Dendrites

A- Dendrites B- Axon C- Axon collateral D- Terminal extensions E- Synaptic knobs

Match the structures with the corresponding letter. A- Perineurium B- Epineurium C- Neurolemmocyte D- Axon E- Endoneurium

A- Epineurium B- Perineurium C- Endoneurium D- Axon E- Neurolemmocyte

A fascicle is a bundle of ______.

Axons

The term ______ means "to bring to".

Afferent

Sensory ______ neurons carry information______ the central nervous system.

Afferent/ Toward

Action potential are always propagated along an axon at the same ______ but ______ can vary depending on the strength of the stimulus.

Amplitude/ Frequency

A substance synthesized at the cell body must undergo ______ transport to reach the synaptic knobs.

Antergrade

The perivascular feet of the ______ help create a blood-brain barrier.

Astrocyte

A cluster of neuron cell bodies found along a peripheral nerve is known as a(n) _________.

Ganglia

A(n) ______ results in a swelling, or enlarged portion, along the length of the nerve, which is often large enough to be observed with the naked eye.

Ganglion

Primary CNS tumors typically originate in tissues that can undergo mitosis like which of the following?

Glial cells and meninges

A ______ ________ is a temporary change in membrane potential which lasts only as long as the stimulus that causes it and can vary in size.

Graded potential

______ occurs when the inside of a cell becomes more negative than the resting membrane potential.

Hyperpolarization

A toxin which interfere with the activity of neuron is called a _______.

Neurotoxin

______ are large cells that ensheath many different axons.

Oligodendrocytes

__________ direction(s) is/ are involved with slow axonal transport occur?

Only anterograde

A nerve is part of the _____ nervous system.

Peripheral

Guillain-Barre syndrome is a disorder of the _______ nervous system.

Peripheral

When sodium ions flow into a cell through a leak channel they make the membrane potential more _____

Positive

The sequential opening of voltage-gated sodium channels is followed by the sequential opening of voltage-gated ________ channels.

Potassium

Propagation of depolarization only flow away from the cell body towards the synaptic knob because _____.

Previous regions in the axon have sodium channels in the inactive state

If an analogy is drawn between an action potential and shooting a gun, then reaching threshold would be analogous to _______.

Pulling the trigger

"An action potential either happens or it doesn't." This statement could also be called _____.

The all-or-none law